1. Field of the Invention
The present invention relates generally to belting and, more particularly, to a belt useful in agricultural applications, such as in hay balers.
2. Description of the Related Art
In agricultural applications, belts are used for a wide variety of purposes, from transmitting power to conveying produce. Hay balers, for instance, use belts to form hay into a bale. Round hay balers use a conveyor belt that travels circumferentially to form a round hay bale. In a typical round hay baler, eight to fifteen rollers support four to eight individual belts, each of which are commonly about 40 feet long.
A round hay baler by have a variable chamber or a fixed chamber. The belts of a variable-chambered round hay baler form a chamber into which hay is fed. The belts compress the hay to form a round hay bale. The belts of a fixed-chamber round hay baler also form an open chamber into which hay is deposited. However, in contrast to variable-chambered round hay balers, the belts do not compress the hay to form a bale. Rather, hay must fill the fixed-chamber in order to form an adequate bale.
Hay balers commonly use cut-edge belts. Mechanical fasteners join the ends of each belt to form an endless belt that is capable of traveling around the rollers in the hay baler. A commonly used mechanical fastener, known as a "clipper lace" splice, is described in U.S. Pat. No. 4,371,580, issued to Morrison, et al. on Feb. 1, 1983. A clipper lace splice includes a plurality of metal eyelets that are connected to each end of the belt. When the eyelets on each end of the belt are aligned with one another, a rod or other suitable retaining material is passed through the eyelets. The ends of the rod are suitably formed to prevent removal of the rod so that the splice remains intact.
Several factors determine the longevity of a belt so constructed. First, the belts are subjected to heavy loads as they travel around the rollers when baling These loads cause the belts to stretch and, thus, fatigue. Second, the belts are subjected to a substantial amount of flexing when travelling around the rollers. Oftentimes, some of the rollers are positioned such that the belts must travel in an S-shape during operation. This flexing typically produces cracks between the plies of a multi-ply belt. Third, the mechanical fasteners tend to wear and fail at a faster rate along the longitudinal edges of the belts. If the mechanical fastener fails, the belt must be replaced before the hay baler can continue operating. Fourth, the edges of the belt tend to curl up against the mechanical guides on the rollers. This curling induces an even greater amount of stress and flexion at the edges of the belt and, thus, contributes to accelerated fatigue in this area of the belt.
While belts have been improved over the years to minimize or overcome various problems, no known belt satisfactorily minimizes or overcomes the problems mentioned above. Two-ply belts, where the plies are made of a polyamide fabric, such as nylon, exhibit excellent flexing characteristics, but also possess a relatively high modulus. In an effort to solve the elongation problem, a two-ply belt was developed where the plies were made of a rayon material. Rayon has a lower modulus than a polyamide fabric and, hence, does not stretch as much as a polyamide belt under the same load. However, the rayon belt proved to be unacceptable, since rayon is particularly susceptible to environmental deterioration caused by moisture. In another attempt to solve the elongation problem, a two-ply belt was developed where the plies were made of a polyester material. This belt proved ineffective since the polyester plies tended to crack when flexed, and the cracking was most pronounced in the area of the mechanical fastener.
A subsequently developed three-ply belt exhibited improved flexing and stretching characteristics as compared with the above-mentioned two-ply belts The center ply was a polyester fabric, and each outer ply was a polyamide fabric. Interposed between the center ply and each outer ply was a rubber skim. These materials were bonded together, and a rubber cover was bonded to each outer ply to provide abrasion protection for the belt and to give the machinery on which the belt was used a surface to engage when the belt was in operation.
However, all of the above-described belts use mechanical fasteners to form an endless belt. Moreover, each of these multi-ply belts tend to delaminate, particularly near the edges of the belt. These problems may continue to plague those skilled in the art due to the method by which such belts are manufactured. Taking the above-described three-ply belt as an example, a brief discussion of conventional manufacturing techniques is in order. First, the fabric of the center ply and the fabrics of the outer plies are primed with Resorcinol Formaldehyde Latex (RFL). The uncured rubber skims and rubber covers are then interposed between the fabric sheets. The stacked sheets are vulcanized to form the appropriate bonds, and the belts are then cut to the appropriate lengths and widths from the three-ply sheet.
The longitudinal edges of the belts produced by this cutting method tend to delaminate when the belts are subjected to the loads and stresses of a hay baling operation. The delamination along the longitudinal edges also contributes to fastener wear near the edges. Moreover, this manufacturing technique produces at least a modicum of waste since some of the material cut from the sheets is thrown away.
The present invention is directed to overcoming, or at least minimizing, one or more of the problems faced by the industry, such as the problems set forth above.